Guidance document
In 2020, Laikre, Hoban and colleagues outlined an approach to assess
genetic diversity status and trends without requiring any genetic
data (e.g. DNA sequence) , using ‘genetic indicators’. The indicators
were developed in response to a recognized gap in reporting to the U.N.
Convention on Biological Diversity (CBD). There was a need for tools to
report on ‘genetic erosion’ and ‘safeguarding’ or ‘maintaining’ genetic
diversity, within and among populations of species. The indicators allow
a fairly standardized and rapid way to assess whether a species is
likely to be losing or has lost genetic diversity by quantifying
critical aspects of demography that generally correlate to genetic
diversity: (1) the size of each population (number of adult
individuals), and (2) the geographic range or number of populations
relative to historic conditions. (A third indicator on genetic
knowledge/ genetic studies has also been proposed, and will be discussed
below).
The logic behind these indicators is simple. (1) Small populations lose
genetic diversity, and very small populations lose genetic diversity
very quickly (Frankham 2021). (2) Loss of populations can result in loss
of unique genetic adaptations (Exposito Alonso et al 2022). So,
measuring population size and loss of populations is a fairly good proxy
or summary of genetic diversity status, without ever measuring the DNA
diversity itself.